That translates to an average of 95 L of water to produce 1 kilowatt-hour of electricity,” says Tamim Younos, associate director of the center and a professor of water resources at Virginia Tech, where the center is housed.

Why so much? Water plays a number of roles in energy production, including pumping crude oil out of the ground, helping to remove pollutants from power plant exhaust, generating steam that turns turbines, flushing away residue after fossil fuels are burned, and keeping power plants cool.

Here are the Virginia Water Resources Research Center results by fuel source:

The researchers also looked at water consumption by type of electricity generation:

This article was corrected on 12 September 2011